I agree that some kind of vfo is the way to go, however, if you come across an old rig with the crystal plugs it's much easier sometimes to just buy one and pop it in. Used to work for a guy in the 90's who had a box full of the old style crystals, (brown bakelite square thingys) mostly ham bands but he also had some bizarre frequencies in there as well. Wish I had bought the lot off of him.